Mercury Transit Timing
Halley's Mercury transit observations strengthen interest in using accurately timed planetary transits to refine measurements of the Solar System.
Astronomer profile · World History Database
Edmond Halley
Edmond Halley was an English astronomer whose work ranged from stellar catalogues and geomagnetism to planetary motion and comets. He is best known for recognising that several recorded comet appearances represented the return of the same object.
Why Edmond Halley matters in astronomy
By predicting the comet’s return, Halley demonstrated the explanatory and predictive power of Newtonian celestial mechanics. The comet now bearing his name became one of astronomy’s most famous periodic objects.
19matching database records
Halley, EdmondName2, Name1 format
Edmond Halley timeline in the database
Transit of Mercury
Halley observes a transit of Mercury from Saint Helena and carefully records the event for later astronomical analysis.
Halley Visit to Newton
Asks Newton what orbit follows from inverse-square attraction, prompting work leading to Principia.
Cometary Orbits
Applies Newtonian gravity to cometary paths and later predicts comet return.
Halley's Comet
Halley is classified as a periodic or short-period comet; one with an orbit lasting 200 years or less. After a rough estimate of the perturbations the comet would sustain from the gravitational attraction of the planets, he predicted its return for 1758
Halley's Comet
This calculation enabled him to determine that the orbital elements of a second comet that had appeared in 1682 were nearly the same as those of two comets that had appeared in 1531 (observed by Petrus Apianus) and 1607 (observed by Johannes Kepler). Halley concluded that all three comets were
Halley's Comet
same object returning every 76 years, a period that has since been amended to every 75-76 years.
Halley's Comet
the
Synopsis of the Astronomy of Comets
Publishes cometary orbit calculations accounting for perturbations by Jupiter and Saturn.
Synopsis of the Astronomy of Comets
Halley publishes his cometary calculations and predicts that the comet seen in 1682 will return in 1758.
Discovery of Nebulae
Edmund Halley publishes a list of six nebulae
Transit of Venus Method
Halley publishes a method for using future transits of Venus to calculate the Earth-Sun distance more accurately.
Astronomer Royal Appointed
Succeeds Flamsteed as Astronomer Royal at Greenwich.
Halleys Comet
Edmund Halley determines that the orbital elements of a comet which had appeared in 1682, were nearly the same as those of two comets which had appeared in 1531 and 1607, Halley thus concludes that they are the same comet.
Halleys Comet
Edmund Halley returns, as predicted in 1682, Halley's Comet last appeared in the inner Solar System in 1986 and will next appear in mid-2061.
Halleys Comet
Halley's Comet is the best-known short-period comet and is visible from Earth every 75 to 76 years.
Halleys Comet
Halleys prediction of the comets return proved to be correct, although it was not seen until 25 December 1758, by Johann Georg Palitzsch, a German farmer and amateur astronome
Halley's Comet
Halley's predicted comet is observed again, confirming his orbital calculation after his death and strengthening Newtonian celestial mechanics.
Halleys Comet
The comet is first named in Halleys honour by French astronomer Nicolas Louis de Lacaille in 1759
Related astronomy topics
Sources and editorial provenance
Compiled and edited by World History Database
Historical chronology compiled from the World History Database and checked against major scientific and historical reference sources.
Last reviewed: September 2026.
- Royal Museums Greenwich — History of astronomy
- Royal Museums Greenwich — History of the telescope
- NASA Science — Hubble timeline
- NASA Science — Exoplanet discovery history
- LIGO — GW150914 first gravitational-wave detection
- Event Horizon Telescope — first black-hole image
- NASA Webb — mission science and discoveries